首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   193篇
  免费   87篇
各国政治   1篇
外交国际关系   7篇
法律   173篇
中国共产党   1篇
中国政治   2篇
政治理论   1篇
综合类   95篇
  2024年   1篇
  2023年   8篇
  2022年   5篇
  2021年   8篇
  2020年   11篇
  2019年   13篇
  2018年   11篇
  2017年   15篇
  2016年   11篇
  2015年   17篇
  2014年   21篇
  2013年   20篇
  2012年   24篇
  2011年   10篇
  2010年   14篇
  2009年   12篇
  2008年   12篇
  2007年   14篇
  2006年   10篇
  2005年   11篇
  2004年   5篇
  2003年   4篇
  2002年   5篇
  2001年   3篇
  2000年   2篇
  1997年   2篇
  1996年   2篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1987年   3篇
  1985年   1篇
排序方式: 共有280条查询结果,搜索用时 15 毫秒
21.
In Europe, authorities frequently ask forensic laboratories to analyze seized cannabis plants to prove that cultivation was illegal (drug type and not fiber type). This is generally done with mature and flowering plants. However, authorities are often confronted with very young specimens. The aim of our study was to evaluate when the chemotype of cannabis plantlets can be surely determined through analysis of eight major cannabinoids content during growth. Drug-type seedlings and cuttings were cultivated, sampled each week, and analyzed by high-performance liquid chromatography with diode array detection. The chemotype of clones was recognizable at any developmental stage because of high total Δ(9)-tetrahydrocannabinol (THC) concentrations even at the start of the cultivation. Conversely, right after germination seedlings contained a low total THC content, but it increased quickly with plant age up, allowing chemotype determination after 3 weeks. In conclusion, it is not necessary to wait for plants' flowering to identify drug-type cannabis generally cultivated in Europe.  相似文献   
22.
Abstract: Consumer complaints received by the U.S. Food and Drug Administration in August 2010 about raw organic almonds tasting “bitter” opened an investigation into the presence of bitter almonds in the imported product. Bitter almonds (Prunus amygdalus) contain the cyanogenic glucoside amygdalin, which hydrolyzes to produce cyanide. Ultraviolet–visible spectrophotometry was used to detect and quantitate cyanide, and liquid chromatography‐mass spectrometry was utilized to detect amygdalin in the submitted samples. Control bitter almonds were found to contain 1.4 mg cyanide/g and an estimated level of 20–25 mg amygdalin/g. The questioned samples contained between 14 and 42 μg cyanide/g and were positive for the presence of amygdalin. Sweet almonds were found to be negative for both compounds, at levels of detection of 4 μg cyanide/g and 200 μg amygdalin/g.  相似文献   
23.
目的:建立基于液基细胞学技术的血样羊水栓塞的诊断方法,并对其有效性进行研究。方法收集羊水栓塞者血液样本,分别用两种直接涂片法(上清涂片法、沉淀涂片法)和两种液基细胞涂片法(自动涂片法、人工涂片法)对血液样本中的羊水成分进行检测,对4种方法的羊水成分检出率进行比较。结果建立的两种液基细胞涂片法的羊水成分检出率(分别为84.6%、92.3%)明显高于直接涂片法(分别为53.8%、61.5%)。结论液基细胞涂片法可以提高羊水栓塞的检出率。  相似文献   
24.
This study highlights the problem of levamisole‐adulterated cocaine in context of active traffic participation. For the purposes of levamisole concentration monitoring in human serum, an analytical method based on LC‐MS/MS and solid‐phase extraction was applied. A Luna 5 μm C18 (2) 100 A, 150 mm × 2 mm column and a mobile phase consisting of A (H2O/methanol = 95/5, v/v) and B (H2O/methanol = 3/97, v/v), both with 10 mM ammonium acetate and with 0.1% acetic acid (pH = 3.2), were used. The validation experiments demonstrated that the method applied was appropriate for levamisole quantification in human serum. For 23% of levamisole‐positive samples, the concentrations exceeded 20 ng/mL. Therefore, the interaction of this drug with cocaine has to be considered as important for active traffic participation. As a consequence, monitoring of levamisole concentration in human serum is recommended, as long as it is used as cocaine adulterant.  相似文献   
25.
目的建立同时测定大麻植物中四氢大麻酚(tetrahydrocannabinol,THC)、大麻二酚(cannabidiol,CBD)和大麻酚(cannabinol,CBN)三种有效成分的高效液相色谱(HPLC)法。方法采用通用C_(18)色谱柱,以乙腈-磷酸盐缓冲液(0.015 mol/L KH_2PO_4)为流动相,流速为1.0 m L/min,检测波长为220 nm,同时收集波长190~400nm的紫外光谱图,并以此光谱图及保留时间作为定性依据。结果所建方法能良好地分离THC、CBD和CBN,三种成分在0.4~40μg/m L范围内线性关系良好(R~2≥0.999 3),回收率大于87%,最低检出限分别为1.8、2.0和1.3 ng,日内精密度与日间精密度均小于5%。结论反相HPLC法简便、快速、准确,适用于大麻植物中THC、CBD和CBN的定性定量检测。  相似文献   
26.
In several medico‐legal cases, bone samples analysis may provide the only source of toxicological information. This case study reports the analysis of a human bone specimen, belonging to a 46‐year‐old man, found 3 months after his death due to cervical–thoracic injuries in a motorcycle accident. Bone specimen was the only available material for toxicological analysis, among few skull hair and rotten skin. Analysis was performed by a newly developed and validated ultra‐high‐pressure liquid chromatography–mass spectrometry/mass spectrometry (UHPLC‐MS/MS) method, following simple and efficient sample pretreatment. The results were in accordance with the man's medical record: Alprazolam and zolpidem were found at 2.2 and 5.4 ng/g of bone, respectively. Both these drugs were prescribed to the deceased.  相似文献   
27.
Fentanyl transdermal patches have been used to treat cancer‐ and noncancer‐related chronic pain. However, its inappropriate or illegal application may cause fatal poisoning. We herein present the case of a Japanese woman in her 40s who was found dead with seven 25‐μg/h fentanyl transdermal patches on her body. We established a detailed toxicological analysis procedure to quantify fentanyl, and its metabolite norfentanyl, and other drugs (acetaminophen, allylisopropylacetylurea, celecoxib, estazolam, promethazine, and sertraline) in human whole blood by ultra‐high‐performance liquid chromatography–tandem mass spectrometry. The measured fentanyl and norfentanyl concentrations in the femoral and cardiac blood were 0.051 and 0.072 μg/mL and 0.033 and 0.076 μg/mL, respectively. The decedent's fentanyl concentrations were consistent with previously reported postmortem blood levels for fatal cases of poisoning by fentanyl transdermal patches. Based on the decedent's case history, autopsy findings, and toxicological analyses, the cause of death was identified as intoxication with transdermal fentanyl.  相似文献   
28.
Bone samples are used for analysis of drugs in decomposed or skeletonized bodies. Toxicological analyses of buried bones are important for determining the causes and circumstances of death. In this study, methamphetamine and amphetamine concentrations in heart blood, thigh muscles, and thighbones were analyzed using solid‐phase extraction with liquid chromatography–tandem mass spectrometry. Methamphetamine concentrations in heart blood, thigh muscle, and thighbone ranged from 0.041 to 0.873 μg/mL, 0.649 to 2.623 μg/g, and 56.543 to 643.371 μg/g, respectively. Thighbone concentrations were significantly higher than those in heart blood or thigh muscles were. Methamphetamine concentrations in buried thighbone (4.010–45.785 μg/g) were significantly lower than those of unburied thighbones were (56.543–643.371 μg/g). Methamphetamine and amphetamine were detected in thighbones buried for 7–180 days. These findings indicate that the methamphetamine concentrations in bone are higher and decrease after burial in soil.  相似文献   
29.
目的研究巴比妥类安眠药在胶束液相色谱中的保留行为,为其应用提供理论基础。方法选择阴离子型表面活性剂十二烷基硫酸钠(SDS)为流动相,分别考察胶束浓度、流动相pH、有机改性剂浓度、柱温等对巴比妥类安眠药保留行为的影响。结果随着胶束浓度增加,有机改性剂浓度增加以及柱温的升高,巴比妥类安眠药在色谱柱上保留能力降低。结论巴比妥类安眠药容量因子与表面活性剂SDS的浓度、有机改性剂浓度以及柱温成良好的线性关系,而巴比妥类安眠药的保留时间与流动相的pH值呈非线性关系。  相似文献   
30.
Chen C  Yan H  Shen BH  Zhuo XY 《法医学杂志》2011,27(1):25-29
目的 建立同时分析尿液中16种抗生素的超高效液相色谱-串联质谱(UPLC-MS、MS)方法.方法 以哌拉西林为内标.尿样中的目标化合物经Oasis HLB固相萃取柱富集、纯化,利用ZORBAX SB-C18色谱柱,以0.1%的甲酸溶液-乙腈为流动相经梯度洗脱分离,采用多反应监测(MRM)模式进行分析.结果各化合物的最低...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号